1. Field of the Invention
The present invention relates to an audio signal output apparatus for outputting audio signals contained in a multiplexed audio signal via a loudspeaker and a headphone.
2. Description of the Related Art
A conventional audio signal output apparatus supports a multiplexed audio signal. A stereophonic audio signal in which audio signals corresponding to different output directions are multiplexed, a multi-lingual audio signal in which audio signals covering multi-lingual languages are multiplexed, and a picture-in-picture audio signal in which an audio signal corresponding to a main picture and an audio signal corresponding to a sub-picture are multiplexed, belong to the multiplexed audio signal.
FIG. 1 is a block diagram showing a conventional audio signal output apparatus for outputting audio signals contained in a multiplexed audio signal via a loudspeaker and a headphone.
The audio signal output apparatus of FIG. 1 comprises an audio processor 1, an audio amplifier 3, a switch 5, a loudspeaker 7 and a headphone 9. The audio processor 1 demultiplexes an input multiplexed audio signal and then signal-processes each of the demultiplexed audio signals. The audio amplifier 3 amplifies audio signals from the audio processor 1 according to volume and balance control commands input by a user, and then outputs the amplified audio signals to the switch 5. The switch 5 outputs the audio signals output from the audio amplifier 3 to the loudspeaker 7 or the headphone 9 according to user's selection. Accordingly, the audio signal output apparatus of FIG. 1 can output the audio signals contained in the multiplexed audio signal via the loudspeaker 7 or the headphone 9 to produce audible sound.
However, since the audio signal output apparatus of FIG. 1 outputs the demultiplexed audio signals to only one of the loudspeaker 7 and the headphone 9, for example, the conventional audio signal output apparatus cannot perform the function of outputting an English language audio signal via the loudspeaker 7 while at the same time outputting a Korean language audio signal via the headphone 9.
In addition, when an audio signal is output via the loudspeaker 7 or when an audio signal is output via the headphone 9, the volume and balance control is performed by the audio amplifier 3. In general, since the volume and balance settings which are controlled with respect to the loudspeaker 7 are not appropriate for the headphone 9, the user should readjust the volume and balance in order to listen to a properly volume-adjusted and balanced audio signal whenever an audio signal output path is changed.